Project Abstract This study will test the validity of a non-visual assessment strategy for stage I pressure ulcers (PUs) among nursing home (NH) residents with light or dark skin tones using a multi-site, longitudinal cohort design. PUs are common, often preventable, and costly; detection of early-stage PUs is important because intervention may prevent decline to more severe PUs. The standard method of detection, visual skin assessment for non- blanchable erythema, is somewhat reliable for individuals with light skin tones but detects changes after skin damage has already occurred. In addition, visual skin assessment fails to detect skin color changes in persons with darkly pigmented skin. Documented health disparities between African Americans and Caucasians for incidence of stage I PUs and prevention intervention may be related to deficiencies in detection. In our prior studies, we showed that a hand-held device that assesses sub-epidermal moisture (SEM), a measure of edema from inflammatory changes in the tissues, identified stage I PUs. Further, SEM was higher (e.g., increased edema and inflammation) when there was no visible skin damage at the time but a stage I PU was visible on the skin one week later; SEM values predicted 26% of the subsequent stage I PUs. Findings were similar in a small sub-sample of NH residents with dark skin tones. We propose to test the validity of this innovative approach to detecting PUs, particularly focusing on residents with dark skin tones; to test threshold SEM values for detecting stage I PUs and detecting progression of stage I PUs to stage II+ PUs. We will recruit 389 NH residents, 62 of whom will have dark skin tones, who are at risk for PU based on the Minimum Data Set Assessment from 24 NHs. Visual skin assessments and blinded SEM measures will be completed by research staff at least weekly for consented residents for 4 months. Skin tone of NH residents will be assessed using color tiles rather than by proxy measures of ethnicity as in previous research. In addition, participant demographics, MDS assessment data on functional level, and comorbid medical conditions will be obtained from medical record review. Risk assessments using the Braden Scale for Predicting Pressure Sores will be collected at baseline. Generalized ordered logistic modeling, appropriately modeling the repeated observations and time-dependent measures, will be used to evaluate the effectiveness of SEM measures to identify future skin damage. Measurement of SEM represents a potentially important tool for decreasing the disparity of prevention interventions between persons with different skin tones.